Miami Beach commissioners approved zoning maps for medical marijuana dispensaries in an initial vote Wednesday, the first step in creating rules that would allow three such businesses to open in the city.

The ordinance creating zones in South, Middle and North Beach where medical marijuana dispensaries can open passed on a 6-1 vote on first reading. Commissioner Joy Malakoff was the sole no vote.

She disagreed with part of the law that deals with parking and she wanted to raise the legal age of those who could patronize dispensaries from 18 to 21. The age change got no support from fellow commissioners.

The zoning map allows South Beach to have a dispensary on a stretch of Fifth Street (although only on the north side, after objections from residents in the South of Fifth neighborhood) and three sections of Alton Road, including one patch at Dade Boulevard.

In Middle Beach, a dispensary could open at the intersection of Pine Tree Drive and 41st Street, or at Mount Sinai Medical Center. Commissioners said the hospital indicated it does not plan to open a dispensary in the near future.

In North Beach, the zoning would apply to the south side of 71st Street from Indian Creek Drive to Collins Avenue, and south on Collins to 69th Street.

No more than three dispensaries would be allowed, one for each zone.

The law, which will come up for a final vote later this month, also limits signage and advertising. The size of each dispensary could not exceed 7,500 square feet. Marijuana would not be allowed to be grown onsite.

Commissioners also gave initial approval to a process for issuing business licenses to dispensaries. Under the ordinance, the Beach would create a lottery system to issue each of the three licenses that would be available.

John Elizabeth Alemán, the commissioner who sponsored both ordinances, said the lottery would eliminate any unwanted lobbying wars that would arise if the licenses were to be awarded through typical competitive bid procedures.

“The goal of that is to remove any shenanigans around whoever ends up with these really valuable licenses,” she said.